Merge tag 'x86-misc-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 updates from Thomas Gleixner:
 "Updates for miscellaneous x86 areas:

   - Reserve a new boot loader type for barebox which is usally used on
     ARM and MIPS, but can also be utilized as EFI payload on x86 to
     provide watchdog-supervised boot up.

   - Consolidate the native and compat 32bit signal handling code and
     split the 64bit version out into a separate source file

   - Switch the ESPFIX random usage to get_random_long()"

* tag 'x86-misc-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/espfix: Use get_random_long() rather than archrandom
  x86/signal/64: Move 64-bit signal code to its own file
  x86/signal/32: Merge native and compat 32-bit signal code
  x86/signal: Add ABI prefixes to frame setup functions
  x86/signal: Merge get_sigframe()
  x86: Remove __USER32_DS
  signal/compat: Remove compat_sigset_t override
  x86/signal: Remove sigset_t parameter from frame setup functions
  x86/signal: Remove sig parameter from frame setup functions
  Documentation/x86/boot: Reserve type_of_loader=13 for barebox

Documentation/x86/boot.rst

@@ -455,6 +455,7 @@ Protocol:	2.00+
 	11 Minimal Linux Bootloader
 	   <http://sebastian-plotz.blogspot.de>
 	12 OVMF UEFI virtualization stack
+	13 barebox
 	== =======================================
 
   Please contact <hpa@zytor.com> if you need a bootloader ID value assigned.

arch/x86/entry/entry_64_compat.S

@@ -61,7 +61,7 @@ SYM_CODE_START(entry_SYSENTER_compat)
 	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rsp
 
 	/* Construct struct pt_regs on stack */
-	pushq	$__USER32_DS		/* pt_regs->ss */
+	pushq	$__USER_DS		/* pt_regs->ss */
 	pushq	$0			/* pt_regs->sp = 0 (placeholder) */
 
 	/*
@@ -197,7 +197,7 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
 	ANNOTATE_NOENDBR
 
 	/* Construct struct pt_regs on stack */
-	pushq	$__USER32_DS		/* pt_regs->ss */
+	pushq	$__USER_DS		/* pt_regs->ss */
 	pushq	%r8			/* pt_regs->sp */
 	pushq	%r11			/* pt_regs->flags */
 	pushq	$__USER32_CS		/* pt_regs->cs */

arch/x86/ia32/Makefile

@@ -3,7 +3,5 @@
 # Makefile for the ia32 kernel emulation subsystem.
 #
 
-obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o
-
 audit-class-$(CONFIG_AUDIT) := audit.o
 obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y)

arch/x86/include/asm/elf.h

@@ -152,10 +152,6 @@ do {						\
 	(elf_check_arch_ia32(x) ||					\
 	 (IS_ENABLED(CONFIG_X86_X32_ABI) && (x)->e_machine == EM_X86_64))
 
-#if __USER32_DS != __USER_DS
-# error "The following code assumes __USER32_DS == __USER_DS"
-#endif
-
 static inline void elf_common_init(struct thread_struct *t,
 				   struct pt_regs *regs, const u16 ds)
 {

arch/x86/include/asm/fpu/signal.h

@@ -13,16 +13,9 @@
 #ifdef CONFIG_X86_64
 # include <uapi/asm/sigcontext.h>
 # include <asm/user32.h>
-struct ksignal;
-int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
-			compat_sigset_t *set, struct pt_regs *regs);
-int ia32_setup_frame(int sig, struct ksignal *ksig,
-		     compat_sigset_t *set, struct pt_regs *regs);
 #else
 # define user_i387_ia32_struct	user_i387_struct
 # define user32_fxsr_struct	user_fxsr_struct
-# define ia32_setup_frame	__setup_frame
-# define ia32_setup_rt_frame	__setup_rt_frame
 #endif
 
 extern void convert_from_fxsr(struct user_i387_ia32_struct *env,

arch/x86/include/asm/segment.h

@@ -135,6 +135,7 @@
 #define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
 #define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
 #define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
+#define __USER32_CS			__USER_CS
 #define __ESPFIX_SS			(GDT_ENTRY_ESPFIX_SS*8)
 
 /* segment for calling fn: */
@@ -210,7 +211,6 @@
 #define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
 #define __USER32_CS			(GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
 #define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
-#define __USER32_DS			__USER_DS
 #define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
 #define __CPUNODE_SEG			(GDT_ENTRY_CPUNODE*8 + 3)
 

arch/x86/include/asm/sighandling.h

@@ -15,4 +15,13 @@
 
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
 
+void __user *
+get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size,
+	     void __user **fpstate);
+
+int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs);
+int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
+int x64_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
+int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
+
 #endif /* _ASM_X86_SIGHANDLING_H */

arch/x86/include/asm/signal.h

@@ -28,11 +28,6 @@ typedef struct {
 #define SA_IA32_ABI	0x02000000u
 #define SA_X32_ABI	0x01000000u
 
-#ifndef CONFIG_COMPAT
-#define compat_sigset_t compat_sigset_t
-typedef sigset_t compat_sigset_t;
-#endif
-
 #endif /* __ASSEMBLY__ */
 #include <uapi/asm/signal.h>
 #ifndef __ASSEMBLY__

arch/x86/kernel/Makefile

@@ -44,7 +44,7 @@ obj-y			+= head_$(BITS).o
 obj-y			+= head$(BITS).o
 obj-y			+= ebda.o
 obj-y			+= platform-quirks.o
-obj-y			+= process_$(BITS).o signal.o
+obj-y			+= process_$(BITS).o signal.o signal_$(BITS).o
 obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y			+= traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o dumpstack.o nmi.o
@@ -54,7 +54,7 @@ obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y			+= probe_roms.o
 obj-$(CONFIG_X86_32)	+= sys_ia32.o
-obj-$(CONFIG_IA32_EMULATION)	+= sys_ia32.o
+obj-$(CONFIG_IA32_EMULATION)	+= sys_ia32.o signal_32.o
 obj-$(CONFIG_X86_64)	+= sys_x86_64.o
 obj-$(CONFIG_X86_ESPFIX64)	+= espfix_64.o
 obj-$(CONFIG_SYSFS)	+= ksysfs.o

arch/x86/kernel/espfix_64.c

@@ -94,17 +94,7 @@ static inline unsigned long espfix_base_addr(unsigned int cpu)
 
 static void init_espfix_random(void)
 {
-	unsigned long rand;
-
-	/*
-	 * This is run before the entropy pools are initialized,
-	 * but this is hopefully better than nothing.
-	 */
-	if (!arch_get_random_longs(&rand, 1)) {
-		/* The constant is an arbitrary large prime */
-		rand = rdtsc();
-		rand *= 0xc345c6b72fd16123UL;
-	}
+	unsigned long rand = get_random_long();
 
 	slot_random = rand % ESPFIX_STACKS_PER_PAGE;
 	page_random = (rand / ESPFIX_STACKS_PER_PAGE)

arch/x86/ia32/ia32_signal.c → arch/x86/kernel/signal_32.c

 // SPDX-License-Identifier: GPL-2.0
 /*
- *  linux/arch/x86_64/ia32/ia32_signal.c
- *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
@@ -26,7 +24,6 @@
 #include <linux/uaccess.h>
 #include <asm/fpu/signal.h>
 #include <asm/ptrace.h>
-#include <asm/ia32_unistd.h>
 #include <asm/user32.h>
 #include <uapi/asm/sigcontext.h>
 #include <asm/proto.h>
@@ -35,6 +32,9 @@
 #include <asm/sighandling.h>
 #include <asm/smap.h>
 
+#ifdef CONFIG_IA32_EMULATION
+#include <asm/ia32_unistd.h>
+
 static inline void reload_segments(struct sigcontext_32 *sc)
 {
 	unsigned int cur;
@@ -53,6 +53,21 @@ static inline void reload_segments(struct sigcontext_32 *sc)
 		loadsegment(es, sc->es | 0x03);
 }
 
+#define sigset32_t			compat_sigset_t
+#define restore_altstack32		compat_restore_altstack
+#define unsafe_save_altstack32		unsafe_compat_save_altstack
+
+#else
+
+#define sigset32_t			sigset_t
+#define __NR_ia32_sigreturn		__NR_sigreturn
+#define __NR_ia32_rt_sigreturn		__NR_rt_sigreturn
+#define restore_altstack32		restore_altstack
+#define unsafe_save_altstack32		unsafe_save_altstack
+#define __copy_siginfo_to_user32	copy_siginfo_to_user
+
+#endif
+
 /*
  * Do a signal return; undo the signal stack.
  */
@@ -86,6 +101,7 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs,
 	/* disable syscall checks */
 	regs->orig_ax = -1;
 
+#ifdef CONFIG_IA32_EMULATION
 	/*
 	 * Reload fs and gs if they have changed in the signal
 	 * handler.  This does not handle long fs/gs base changes in
@@ -93,10 +109,17 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs,
 	 * normal case.
 	 */
 	reload_segments(&sc);
+#else
+	loadsegment(gs, sc.gs);
+	regs->fs = sc.fs;
+	regs->es = sc.es;
+	regs->ds = sc.ds;
+#endif
+
 	return fpu__restore_sig(compat_ptr(sc.fpstate), 1);
 }
 
-COMPAT_SYSCALL_DEFINE0(sigreturn)
+SYSCALL32_DEFINE0(sigreturn)
 {
 	struct pt_regs *regs = current_pt_regs();
 	struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
@@ -119,7 +142,7 @@ COMPAT_SYSCALL_DEFINE0(sigreturn)
 	return 0;
 }
 
-COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
+SYSCALL32_DEFINE0(rt_sigreturn)
 {
 	struct pt_regs *regs = current_pt_regs();
 	struct rt_sigframe_ia32 __user *frame;
@@ -129,7 +152,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
 
 	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;
-	if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
+	if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
 		goto badframe;
 
 	set_current_blocked(&set);
@@ -137,7 +160,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
 	if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
 
-	if (compat_restore_altstack(&frame->uc.uc_stack))
+	if (restore_altstack32(&frame->uc.uc_stack))
 		goto badframe;
 
 	return regs->ax;
@@ -159,9 +182,15 @@ __unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc,
 			    struct pt_regs *regs, unsigned int mask)
 {
 	unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault);
+#ifdef CONFIG_IA32_EMULATION
 	unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault);
 	unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault);
 	unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault);
+#else
+	unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
+	unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
+	unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
+#endif
 
 	unsafe_put_user(regs->di, &sc->di, Efault);
 	unsafe_put_user(regs->si, &sc->si, Efault);
@@ -196,43 +225,9 @@ do {									\
 		goto label;						\
 } while(0)
 
-/*
- * Determine which stack to use..
- */
-static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
-				 size_t frame_size,
-				 void __user **fpstate)
-{
-	unsigned long sp, fx_aligned, math_size;
-
-	/* Default to using normal stack */
-	sp = regs->sp;
-
-	/* This is the X/Open sanctioned signal stack switching.  */
-	if (ksig->ka.sa.sa_flags & SA_ONSTACK)
-		sp = sigsp(sp, ksig);
-	/* This is the legacy signal stack switching. */
-	else if (regs->ss != __USER32_DS &&
-		!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
-		 ksig->ka.sa.sa_restorer)
-		sp = (unsigned long) ksig->ka.sa.sa_restorer;
-
-	sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
-	*fpstate = (struct _fpstate_32 __user *) sp;
-	if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
-				      math_size))
-		return (void __user *) -1L;
-
-	sp -= frame_size;
-	/* Align the stack pointer according to the i386 ABI,
-	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
-	sp = ((sp + 4) & -16ul) - 4;
-	return (void __user *) sp;
-}
-
-int ia32_setup_frame(int sig, struct ksignal *ksig,
-		     compat_sigset_t *set, struct pt_regs *regs)
+int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs)
 {
+	sigset32_t *set = (sigset32_t *) sigmask_to_save();
 	struct sigframe_ia32 __user *frame;
 	void __user *restorer;
 	void __user *fp = NULL;
@@ -264,7 +259,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 	if (!user_access_begin(frame, sizeof(*frame)))
 		return -EFAULT;
 
-	unsafe_put_user(sig, &frame->sig, Efault);
+	unsafe_put_user(ksig->sig, &frame->sig, Efault);
 	unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
 	unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
 	unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
@@ -280,15 +275,20 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 
 	/* Make -mregparm=3 work */
-	regs->ax = sig;
+	regs->ax = ksig->sig;
 	regs->dx = 0;
 	regs->cx = 0;
 
-	loadsegment(ds, __USER32_DS);
-	loadsegment(es, __USER32_DS);
+#ifdef CONFIG_IA32_EMULATION
+	loadsegment(ds, __USER_DS);
+	loadsegment(es, __USER_DS);
+#else
+	regs->ds = __USER_DS;
+	regs->es = __USER_DS;
+#endif
 
 	regs->cs = __USER32_CS;
-	regs->ss = __USER32_DS;
+	regs->ss = __USER_DS;
 
 	return 0;
 Efault:
@@ -296,9 +296,9 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 	return -EFAULT;
 }
 
-int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
-			compat_sigset_t *set, struct pt_regs *regs)
+int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 {
+	sigset32_t *set = (sigset32_t *) sigmask_to_save();
 	struct rt_sigframe_ia32 __user *frame;
 	void __user *restorer;
 	void __user *fp = NULL;
@@ -321,7 +321,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 	if (!user_access_begin(frame, sizeof(*frame)))
 		return -EFAULT;
 
-	unsafe_put_user(sig, &frame->sig, Efault);
+	unsafe_put_user(ksig->sig, &frame->sig, Efault);
 	unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault);
 	unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault);
 
@@ -331,7 +331,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 	else
 		unsafe_put_user(0, &frame->uc.uc_flags, Efault);
 	unsafe_put_user(0, &frame->uc.uc_link, Efault);
-	unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
+	unsafe_save_altstack32(&frame->uc.uc_stack, regs->sp, Efault);
 
 	if (ksig->ka.sa.sa_flags & SA_RESTORER)
 		restorer = ksig->ka.sa.sa_restorer;
@@ -357,15 +357,20 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 
 	/* Make -mregparm=3 work */
-	regs->ax = sig;
+	regs->ax = ksig->sig;
 	regs->dx = (unsigned long) &frame->info;
 	regs->cx = (unsigned long) &frame->uc;
 
-	loadsegment(ds, __USER32_DS);
-	loadsegment(es, __USER32_DS);
+#ifdef CONFIG_IA32_EMULATION
+	loadsegment(ds, __USER_DS);
+	loadsegment(es, __USER_DS);
+#else
+	regs->ds = __USER_DS;
+	regs->es = __USER_DS;
+#endif
 
 	regs->cs = __USER32_CS;
-	regs->ss = __USER32_DS;
+	regs->ss = __USER_DS;
 
 	return 0;
 Efault:

arch/x86/xen/xen-asm.S

@@ -262,10 +262,10 @@ SYM_CODE_START(xen_entry_SYSCALL_compat)
 
 	/*
 	 * Neither Xen nor the kernel really knows what the old SS and
-	 * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
+	 * CS were.  The kernel expects __USER_DS and __USER32_CS, so
 	 * report those values even though Xen will guess its own values.
 	 */
-	movq $__USER32_DS, 4*8(%rsp)
+	movq $__USER_DS, 4*8(%rsp)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSCALL_compat_after_hwframe
@@ -284,10 +284,10 @@ SYM_CODE_START(xen_entry_SYSENTER_compat)
 
 	/*
 	 * Neither Xen nor the kernel really knows what the old SS and
-	 * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
+	 * CS were.  The kernel expects __USER_DS and __USER32_CS, so
 	 * report those values even though Xen will guess its own values.
 	 */
-	movq $__USER32_DS, 4*8(%rsp)
+	movq $__USER_DS, 4*8(%rsp)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSENTER_compat_after_hwframe

include/linux/compat.h

@@ -126,11 +126,9 @@ struct compat_tms {
 
 #define _COMPAT_NSIG_WORDS	(_COMPAT_NSIG / _COMPAT_NSIG_BPW)
 
-#ifndef compat_sigset_t
 typedef struct {
 	compat_sigset_word	sig[_COMPAT_NSIG_WORDS];
 } compat_sigset_t;
-#endif
 
 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
 			    size_t sigsetsize);

include/linux/syscalls.h

@@ -264,6 +264,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
 #define SC_VAL64(type, name) ((type) name##_hi << 32 | name##_lo)
 
 #ifdef CONFIG_COMPAT
+#define SYSCALL32_DEFINE0 COMPAT_SYSCALL_DEFINE0
 #define SYSCALL32_DEFINE1 COMPAT_SYSCALL_DEFINE1
 #define SYSCALL32_DEFINE2 COMPAT_SYSCALL_DEFINE2
 #define SYSCALL32_DEFINE3 COMPAT_SYSCALL_DEFINE3
@@ -271,6 +272,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
 #define SYSCALL32_DEFINE5 COMPAT_SYSCALL_DEFINE5
 #define SYSCALL32_DEFINE6 COMPAT_SYSCALL_DEFINE6
 #else
+#define SYSCALL32_DEFINE0 SYSCALL_DEFINE0
 #define SYSCALL32_DEFINE1 SYSCALL_DEFINE1
 #define SYSCALL32_DEFINE2 SYSCALL_DEFINE2
 #define SYSCALL32_DEFINE3 SYSCALL_DEFINE3